Investments, At Equity, And Advances To 50% Or Less Owned Companies (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended						6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 Mexmar [Member]	Jun. 30, 2012 Aeroleo Taxi Aereo S/A [Member]	Jun. 30, 2012 Illinois Corn Processing LLC [Member]	Feb. 01, 2012 Illinois Corn Processing LLC [Member]	Jun. 30, 2012 Hawker Pacific Airservices, Limited [Member]	Mar. 31, 2012 Hawker Pacific Airservices, Limited [Member]	Jun. 30, 2012 SCFCo Holdings [Member]	Jun. 30, 2012 Avion Pacific Limited [Member]	Jun. 30, 2012 Trailer Bridge Inc [Member]	Apr. 02, 2012 Trailer Bridge Inc [Member]	Feb. 01, 2012 ICP Acquisition [Member]	Apr. 02, 2012 Title Eleven Bonds [Member] Trailer Bridge Inc [Member]
Schedule Of Equity Method Investments [Line Items]
Partners' Capital Account, Contributions								$ 500,000				$ 500,000
Equity Method Investment, Ownership Percentage									70.00%						47.30%	70.00%
Investments, Fair Value Disclosure															9,900,000
Equity Method Investments, Inclusive of Secured Debt															48,100,000
Investment Owned, at Fair Value															43,000,000
Long-Term Debt	940,910,000		940,910,000		995,450,000												5,100,000
Bridge Loan															15,700,000
Marketable Securities, Gain (Loss)	11,596,000	(4,754,000)	14,954,000	(3,220,000)										9,800,000
Cash paid on acquisition									9,100,000
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain								6,000,000
Advances made under revolving line of credit								300,000
Equity Method Investment Impairment							5,900,000
Loans/notes receivable						31,800,000							5,000,000
Sales Price Of Equipment			65,600,000			50,000,000
Payments to Acquire Machinery and Equipment						5,000,000
Debt instrument, stated percentage											10.00%				9.25%
Secured Debt						45,000,000									33,100,000
Advanced to joint ventures										3,300,000			9,000,000
Received repayments of line of credit						(14,100,000)							(13,700,000)
Guarantor Obligations, Maximum Exposure, Undiscounted	24,600,000		24,600,000
Allocable Share of Uncalled Capital	$ 2,400,000		$ 2,400,000